Does anybody understand the social security system in Austria??

I have set myself up as a freelancer in Austria - by far the most complicated, ridiculous, expensive, fractured and overcomplicated system I've ever had to deal with.
I have a steuerberater (currently away hence request for knowledge) and have received my e-card. I've also received a giant SVA pack with all the social security information. Unfortunately my German isnt great and even google translate can;t hep me decipher what I'm reading. From what I can tell I have to choose which pension on health insurance body will control my social security (what??). There are around 11 different ones named. That's as much as I understand. I have no idea how to do this and all the forms presented are not for self employed. I tried their website but I can't eve contact anybody until Ive chosen the governing body.

I'm completely lost. Does anybody have any idea what I do??

many thanks